We will develop a wireless digital polygraph link with sophisticated digital error correction, which will protect transmitted physiological measurement signals from noise degradation and from dropouts caused by subjects moving around while they are being monitored. We will add the wireless digital link to a miniature, battery-operated 16-channel microprocessor-based digital polygraph previously developed under a PHS SBIR Phase II grant. With the existing device, the wireless digital link will make possible true wireless polygraphic monitoring. It will open up new areas of investigation involving infants and children, freely moving subjects, exercising subjects, uncooperative subjects, and subjects who must be studied outside the laboratory. No suitable equipment is now available. Existing polygraphs are too large, and require connecting cables. Some self-contained ambulatory monitors have multiple channel measuring capabilities, but their use is inherently restricted by their internal data storage capacities. Wireless devices avoid these size and data storage limitations; however, few available devices have enough channels to serve as a practical, general-purpose research tool, most employ troublesome analog transmission methods, and none have modular measurement capability.